package com.zhb.framework.util;

import org.apache.commons.lang3.StringUtils;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

import java.io.File;
import java.io.FileFilter;
import java.net.JarURLConnection;
import java.net.URL;
import java.util.Enumeration;
import java.util.HashSet;
import java.util.Set;
import java.util.jar.JarEntry;
import java.util.jar.JarFile;

/**
 * 类操作工具类
 */
public final class ClassUtil {

    private static final Logger log = LoggerFactory.getLogger(ClassUtil.class);

    /**
     * 获取类加载器
     * @return
     */
    public static ClassLoader getClassLoader(){
        return Thread.currentThread().getContextClassLoader();
    }

    /**
     * 加载类
     * @param className  类名
     * @param isInitialized  是否初始化,可以将该参数设置为false，不初始化对象以提高性能
     * @return
     */
    public static Class<?> loadClass(String className, boolean isInitialized){
        Class<?> clazz;
        try {

            clazz = Class.forName(className, isInitialized, getClassLoader());
        }catch (ClassNotFoundException e){
            log.error("load class failure", e);
            throw new RuntimeException();
        }

        return clazz;
    }


    /**
     * 获取指定报名下的所有类
     * @param packageName
     * @return
     */
    public static Set<Class<?>> getClassSet(String packageName){
        Set<Class<?>> classSet = new HashSet<Class<?>>();

        try {
            Enumeration<URL> urls = getClassLoader().getResources(packageName.replace(".","/"));
            while (urls.hasMoreElements()){
                URL url = urls.nextElement();
                if (url != null){
                    String protocol = url.getProtocol();

                    if ("file".equals(protocol)){
                        String packagePath = url.getPath().replace("%20", "");
                        addClass(classSet, packagePath, packageName);

                    }else if ("jar".equals(protocol)){

                        JarURLConnection jarURLConnection = (JarURLConnection) url.openConnection();
                        if (jarURLConnection != null){
                            JarFile jarFile = jarURLConnection.getJarFile();
                            if (jarFile != null){
                                Enumeration<JarEntry> jarEntries = jarFile.entries();

                                while (jarEntries.hasMoreElements()){

                                    JarEntry jarEntry = jarEntries.nextElement();
                                    String jarEntryName = jarEntry.getName();

                                    if (jarEntryName.endsWith(".class")){
                                        String className = jarEntryName.substring(0,jarEntryName.lastIndexOf("."))
                                                .replace("/","");
                                        doAddClass(classSet, className);
                                    }
                                }
                            }
                        }
                    }
                }
            }

        }catch (Exception e){
            log.error("get class set failure",e);
            throw new RuntimeException();
        }
        return classSet;
    }

    private static void addClass(Set<Class<?>> classSet, String packagePath, String packageName){
        File[] files = new File(packagePath).listFiles(new FileFilter() {
            public boolean accept(File file) {
                return (file.isFile() && file.getName().endsWith(".class")) || file.isDirectory();
            }
        });

        for (File file : files){
            String fileName = file.getName();
            if (file.isFile()){
                String className = fileName.substring(0,fileName.lastIndexOf("."));

                if (StringUtils.isNotBlank(packageName)){
                    className = packageName+"."+className;
                }
                doAddClass(classSet,className);
            }else {
                String subPackagePath = fileName;

                if (StringUtils.isNotBlank(packagePath)){
                    subPackagePath = packagePath + "/" + subPackagePath;
                }

                String subPackageName = fileName;

                if (StringUtils.isNotBlank(packageName)){
                    subPackageName = packageName + "." + subPackageName;
                }

                addClass(classSet, subPackagePath, subPackageName);
            }
        }
    }

    private static void doAddClass(Set<Class<?>> classSet, String className){
        Class<?> clazz = loadClass(className, false);
        classSet.add(clazz);
    }


}
